The present invention relates generally to a diagnostic system for an automotive vehicle of the type having (1) a network of sensors and actuators for independently sensing and actuating a number of different functions within the vehicle and (2) an onboard computer for monitoring the sensors and controlling the operation of the actuators. The present invention relates more particularly to what may be referred to as an interactive system for diagnosing the performance of a vehicle (1) by controlling the operation of one or more of its specific actuators independent of its onboard computer, (2) by simulating the operation of one or more of its specific sensors independent of the actual operation of those sensors, and (3) by continuously monitoring and analyzing the other vehicle actuators and sensors and, in fact, all of the electronic data entering and/or exiting the onboard computer, preferably, in real time.
It is a fact that most new cars and trucks, that is, automotive vehicles generally, are far more sophisticated than their predecessors. As exemplified in FIG. 1, a typical vehicle manufactured today, generally indicated at 8, includes an onboard computer 10 which is generally referred to as an electronic control module. This ECM serves to control the operation of one or more specific actuators associated with the vehicle's auto drive system 12 including its engine and other components by responding to the network of corresponding sensors. Typical actuators which are usually solenoids, although not always, might include fuel injectors, an air diverter valve, an ignition module, valves associated with anti-lock brakes, as well as others, some of which are illustrated in FIG. 1. Typical sensors may include temperature sensors, oxygen level sensors, sensors associated with anti-lock brakes and so on, some of which are also illustrated in FIG. 1. The way in which these components interrelate with one another and with the electronic control module may be best exemplified by the way in which fuel injection is controlled as a function of oxygen levels within the engine. More specifically, the ECM uses an oxygen sensor in the exhaust manifold to sense the oxygen level there and, at the same time, it operates the fuel injector through an associated solenoid. Thus, if the ECM senses an increase in oxygen, it will automatically increase fuel consumption by appropriately operating the fuel injection solenoid and, if it senses a decrease in oxygen, it will automatically decrease fuel consumption by means of the same solenoid, thus achieving optimal emission levels.
Still referring to FIG. 1, a typical arrangement 14 for electrically connecting the ECM 10 with its network of actuators and sensors 12 is illustrated. This connection arrangement includes an auto-side connector 16 having a series of auto-side plug-in terminals 18 respectively connected with associated sensors and actuators and a computer-side connector 20 disengageably connectable to the auto-side connector by means of corresponding, complementary computer-side plug-in terminals 22 connected to the appropriate circuitry within electronic control module 10. In the embodiment illustrated in FIG. 1, the auto-side terminals 18 are shown as the male terminals and the computer-side terminals 22 are shown as female terminals. For purposes of clarity, cooperating terminals 18, 22 are designated T1, T2, T3 and so on. Only ten such terminals have been illustrated for purposes of convenience but in today's vehicles, there can be as may as 100 such terminals. The components connected with these terminals vary between different vehicle makes and models. For example, the oxygen sensor might be associated with terminal T1 in one vehicle and T5 in another. Vehicle makes and models may include sensors and actuators that other vehicle makes and models do not have. For example, a knock sensor used to sense engine knocks, which result in the ECM retarding spark timing, is found generally only in more expensive cars.
Having described the present-day high tech automotive vehicle, attention is now directed to one prior art way in which it can be serviced. Specifically, the automotive service professional might use what is commonly referred to as a "breakout box", generally indicated by the reference numeral 24, for gaining access to all of the terminals T1-T10. To this end, the breakout box has its own adaptor 26 disposed between and connecting together auto-side connector 16 with computer-side connector 20 such that each terminal 18 remains connected to its associated terminal 22. At the same time, adaptor 26 is connected to the breakout box through a connecting harness 28 for electrically connecting the breakout box's own terminals 30 to corresponding terminals T1, T2, T3 and so on. In this way, the automotive service professional can easily gain access to any of the terminals T1-T10 by means of terminals 30.
In actual practice, the breakout box 24 is typically used by the automotive service professional to diagnose a problem associated with energization of a trouble light on the dashboard of the vehicle in question. Many vehicle makes and models include their own trouble code associated with each given trouble light. Typically, a trouble code indicates some abnormal condition in a given circuit within the vehicle's electronic system. For example, trouble code 42 on a GM vehicle may indicate abnormal voltage readings from the oxygen sensor. Thus, on a vehicle with code 42 set, a professional may connect the breakout box 24 and insert a voltmeter into the terminal associated with the oxygen sensor on that particular vehicle, say terminal T:, and verify the actual voltage in the circuit. It is worthwhile noting that whereas some trouble codes are very specific, others are quite general and in many cases the same code will be set for many different problems; further more, many problems will cause the setting of multiple trouble codes.
It is important to note that the diagnostic system associated with the breakout box 24, as described above, is a passive system. That is, the automotive service professional uses the breakout box to access the connector terminals in order to observe the components associated with those terminals typically by connecting a volt meter and from those observations, he is hopefully able to diagnose the problem.
There are a number drawbacks associated with the passive diagnostic approach just described utilizing breakout box 24. One obvious drawback relates to the time it takes to make the diagnosis. An appropriate manual for each given vehicle make and model must be kept and reviewed in order to determine which terminals to access and what to look for, depending upon the particular trouble light that is flashing and the particular vehicle. In many cases, the trouble that is described by the vehicle operator does not always result in a flashing trouble light or the trouble is intermittent and does not always occur at the time the vehicle is being diagnosed. After an extended diagnostic period, the problem may not be found or its results suspect. Moreover, the problem may only occur under certain conditions that cannot be duplicated at the service station. For example, evaluating problems associated with the air management system often require that the vehicle's engine be under load. Of course, this is not possible using breakout box 24 without actually driving the vehicle.